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- Posts: 48
- Joined: Thu Jun 01, 2017 12:58 pm
- Location: Denmark
I'm trying to optimize a custom-designed GC that I'm building myself, and I've run into a strange issue.
With a 3 ft packed 1/8" (ca. 2mm ID) column packed with untreated bentonite (80-100 mesh) i get baseline separation between n-propane and n-butane (the standard i use since the column is at room temp.)
with a 4 ft "micro-packed" 1/16" (ca. 1mm id) packed column with same stationary phase I get no separation at all.
I know it's a difficult thing to comment on, given nothing is from a commercial GC system, but what could I have missed?
There's quite a bit of dead space in my detector, could the decreased sample throughput of the smaller column mean the components have time to diffuse together again after the column, before the detector?
both columns were run at 30 PSI head pressure at which the 1/8" column have a flow of 25 ml/min
The detector is a 4-element TCD built into compression fitting Tee's.
Thanks in advance!
-Chris